Today Channel Four announced that Time Team would cease to be broadcast after Series 20, which goes out early next year. So what went right? How come we managed to keep a big-budget TV series on the nation’s free-view screens for twenty years? That’s an extraordinary achievement. Time Team has been the longest-running archaeological series in the history of television. There’s going to be a documentary about the history of Time Team, which is currently being filmed, so I don’t want to pre-empt any of its conclusions, but it’s essentially a story of humble origins, steady growth, a huge flourishing – what could be bigger than a synchronised ‘live’ dig at Buckingham Palace, Windsor Castle and Holyrood House – and a rather sad, if mercifully short, decline, which reached its worst in Series 19. I’ll talk about the decline shortly, but first a few words about why I think Time Team worked so well for so long.

I think the main reason is simple, like the idea at the programme’s heart. Time Team is a true reality show: it reflects the real world of a true-life excavation. Thousands of smaller versions of Time Team happen every year in the world of commercial archaeology. These rapid, often small-scale excavations are known as assessments and they’re the first stage that any developer has to go through ahead of a major scheme, such as a housing estate, new road or gravel pit. After that first investigation, there’s often a larger-scale rescue excavation which focuses on areas of interest revealed by the assessment. So, claims often made by some hostile academics, that our three-day format is somehow false, are simply not true. And for what it’s worth, I fear that already hard-pressed university archaeology departments will find fewer students enrolling for their courses, once Time Team is no longer on our screens.

The simple three-day format worked well because it was conceived by an archaeologist (Mick Aston) and a film-maker (Tim Taylor) who had, and still has, a deep interest in archaeology. So its roots, its very heart and soul, lie within real-world, hands-on, practical archaeology. That’s the original format’s greatest strength. Then, in 1999, we were able to persuade Tim and Channel 4 to make the first of their documentaries (at the time they were known as ‘specials’), which departed from the strict 3-day format. This one was on the Early Bronze Age timber circle at Holme-next-the-Sea, in Norfolk, today known to the world as Seahenge. There have been many more made since then, but few have been bettered. I can’t think why my wife Maisie wasn’t offered a job in feature films by MGM. Trouble is, she’d have turned them down. But I digress.

As the years rolled by, Time Team became bigger and bigger, with more people and personalities. In some respects this was good, as it meant we could take on more ambitious subjects and do them justice, but it also meant that each programme had to be more tightly scripted. So spontaneity, especially as regards what was happening hour-by-hour in the trenches, began to be lost. By Series 19 there was scarcely a scene shot of anything actually coming out of the ground. This so disgusted Mick Aston that he walked off. I should add that matters had not been improved by Channel 4 who made a number of inexplicable changes to transmission times and for two or three series failed to provide any advance publicity. All in all, the scheduling of the last few series was a mess.

I would have walked off with Mick, as I still have sympathy with him, but I believed the assurances I was given by the Producers, that the prime focus would return to archaeology. I have to say I did have a few remaining doubts, but decided to give them one more chance. Thankfully, that first shoot – at a hillfort in Wales – was just like old times: lots of archaeology and no superfluous, silly ‘history’ scenes. And the remaining five episodes I filmed were, I think, first rate. And that was in great part due to the efforts of Jim Mower, the Development Producer (also an archaeologist), who arranged a great succession of sites for us. The Machine Gun Corps training camp, the copper mine in Cumbria and the Roman Saxon Shore Fort were outstanding. It’s a terrible shame that the programme rediscovered its roots too late. But at least we can say we sank with our heads held high. The orchestra was playing in the dining salon, as the waters lapped at our chins. I knew it was a mistake to trowel-through the hull.

And the future – is there one? Channel Four have announced that they will commission 4 or 5 Time Team documentaries in 2013 and there are plans afoot to re-invent the format on a smaller scale on the internet. But unless something miraculous happens I’m afraid that’s it – certainly for the time-being.

And what are my plans? With luck I’ll take part in one of the documentaries, but I’m being leant on by the nice people at Penguin to produce the book I should have delivered last May, were it not for Series 20. So I’ll be getting back to what I enjoy most of all: writing. And of course this blog will continue, getting ever-more testy, ill-considered and intemperate as the weeks, months and years roll by. I can hardly wait – can you?